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Saline‐alkali soils cover an area of more than 900 million ha and pose an acute threat to global food security. Rice cultivation is an effective method of saline‐sodic soil amelioration in the Songnen Plain in northeastern China. However, the changes in soil microbial communities that follow rice cultivation are largely unknown. In this study, soil bacterial and fungal communities were investigated using high‐throughput sequencing along a chronosequence of rice paddies cultivated in saline‐sodic soils. The results showed that soil fungi and bacteria become more diverse and abundant after rice cultivation compared with uncultivated saline‐sodic soil, in combination with the decreased pH and increased soil organic matter, indicating the amelioration of saline‐sodic soil. The processes of microbial succession following rice cultivation can be divided into two stages: shorter than and longer than 10 years. Moreover, soil fungi and bacteria exhibited distinct variation patterns as they were dominated by different influential factors. The results indicated that bacteria were more strongly dominated by soil properties than fungi, while the latter were more dependent on vegetation. As rice cultivation continued, fungi exhibited better adaptation and faster succession than bacteria in response to environmental shifts after rice cultivation. Therefore, measures that can enhance plant–microbe interactions may be a viable approach for promoting saline‐sodic soil amelioration. This study provided novel insights into the microbial assembly processes following rice cultivation on saline‐sodic lands. [ABSTRACT FROM AUTHOR]

Background: The Songnen Plain in northeast China was one of three major grasslands in China and has now become one of the most concentrated areas of sodic‐saline soil worldwide due to soil parent material characteristics, hydrological conditions, and overgrazing. Aims: The aim of this study was to evaluate the direct effects of environmental factors in shaping prokaryotic communities under three natural contiguous areas (severe saline‐alkaline field with no vegetation, moderate saline‐alkaline field with Suaeda glauca, and mildly saline‐alkaline field with natural grass vegetation) on the Songnen Plain in northeast China. Methods: Physicochemical properties of the soil pH, electric conductivity (EC), and soil organic carbon (SOC) were determined in three soil types with or without vegetation, while the metabarcoding analysis of the prokaryotic diversity and composition were analyzed by Illumina Miseq sequencing. Results: Our study revealed that the moderate and mildly saline‐alkaline soil exhibited lower pH by 0.614% and 10.17%, and significantly lower EC by 47.96% and 89.22%, respectively, in comparison to severe saline‐alkaline field soil. Prokaryotic 16S rRNA gene amplicon analysis revealed that mildly saline‐alkaline soil with native grasses had significantly higher alpha‐diversity. The composition of the prokaryotic community was highly correlated with the soil physicochemical properties, but the SOC was the most important driving forces for the prokaryotic composition. Random matrix theory (RMT) network analysis revealed the keystone operational taxonomic unit (OTU) (OTU3096, OTU137, OTU3198 and OTU2210) that was significantly affected by the soil physicochemical properties in the three contiguous areas. Conclusions: Collectively, these findings demonstrate that the mildly saline‐alkaline soil with natural grass vegetation has a beneficial impact on the soil physical properties and prokaryotic community relative to severe saline areas in the Songnen Plain of northeast China. [ABSTRACT FROM AUTHOR]

SUMMARY: Functional analyses of various strigolactone‐deficient mutants have demonstrated that strigolactones enhance drought resistance; however, the mechanistic involvement of the strigolactone receptor DWARF14 (D14) in this trait remains elusive. In this study, loss‐of‐function analysis of the D14 gene in Arabidopsis thaliana revealed that d14 mutant plants were more drought‐susceptible than wild‐type plants, which was associated with their larger stomatal aperture, slower abscisic acid (ABA)‐mediated stomatal closure, lower anthocyanin content and delayed senescence under drought stress. Transcriptome analysis revealed a consistent alteration in the expression levels of many genes related to the observed physiological and biochemical changes in d14 plants when compared with the wild type under normal and dehydration conditions. A comparative drought resistance assay confirmed that D14 plays a less critical role in Arabidopsis drought resistance than its paralog karrikin receptor KARRIKIN INSENSITIVE 2 (KAI2). In‐depth comparative analyses of the single mutants d14 and kai2 and the double mutant d14 kai2, in relation to various drought resistance‐associated mechanisms, revealed that D14 and KAI2 exhibited a similar effect on stomatal closure. On the other hand, D14 had a lesser role in the maintenance of cell membrane integrity, leaf cuticle structure and ABA‐induced leaf senescence, but a greater role in drought‐induced anthocyanin biosynthesis, than KAI2. Interestingly, a possible additive relationship between D14 and KAI2 could be observed in regulating cell membrane integrity and leaf cuticle development. In addition, our findings also suggest the existence of a complex interaction between the D14 and ABA signaling pathways in the adaptation of Arabidopsis to drought. Significance Statement: The signaling pathways mediated by two paralogous proteins, the strigolactone receptor DWARF14 and the karrikin receptor KARRIKIN INSENSITIVE 2, show both overlapping and specific responses in affecting various physiological and biochemical processes to positively modulate Arabidopsis adaptation to drought. Data obtained from the transcriptome analysis support our findings at a molecular level. [ABSTRACT FROM AUTHOR]

Cultivated soybean (Glycine max) was derived from the wild soybean (Glycine soja), which has genetic resources that can be critically important for improving plant stress resistance. However, little information is available pertaining to the molecular and physiochemical comparison between the cultivated and wild soybeans in response to the pathogenic Fusarium oxysporum Schltdl. In this study, we first used comparative phenotypic and paraffin section analyses to indicate that wild soybean is indeed more resistant to F. oxysporum than cultivated soybean. Genome‐wide RNA‐sequencing approach was then used to elucidate the genetic mechanisms underlying the differential physiological and biochemical responses of the cultivated soybean, and its relative, to F. oxysporum. A greater number of genes related to cell wall synthesis and hormone metabolism were significantly altered in wild soybean than in cultivated soybean under F. oxysporum infection. Accordingly, a higher accumulation of lignins was observed in wild soybean than cultivated soybean under F. oxysporum infection. Collectively, these results indicated that secondary metabolites and plant hormones may play a vital role in differentiating the response between cultivated and wild soybeans against the pathogen. These important findings may provide future direction to breeding programs to improve resistance to F. oxysporum in the elite soybean cultivars by taking advantage of the genetic resources within wild soybean germplasm. [ABSTRACT FROM AUTHOR]

Soil microbes play critical roles in global biogeochemical cycles, but their succession patterns across long temporal scales have rarely been studied. In this study, soil samples were collected from three volcanoes in Wudalianchi, northeastern China: Laoheishan (LH, approximately 240 years old), Dongjiaodebushan (DJ, 0.45–0.6 million years old), and Nangelaqiushan (NG, 0.8–1.3 million years old). For each volcano, both southern (S) and northern (N) slope aspects were sampled. Soil microbial communities were analyzed using phospholipid fatty acid analysis (PLFA). The results showed that soil properties and microbial biomass changed perceptibly among different volcanoes and different slope aspects. Almost all of the detected soil nutrient contents of LH were lowest, and total microbial biomass of LH was 40 and 36% lower than those of NG and DJ, respectively. LH was significantly different from NG and DJ in soil microbial community structure with a higher relative abundance of fungi and a lower relative abundance of actinomycetes and bacteria. However, for the two ancient volcanoes (NG and DJ), soil microbial community structures were highly similar among different ages and different slope aspects. No difference was detected in any of the measured microbial indices, including richness, evenness, Shannon's diversity, Simpson's diversity and the relative abundance of different microbial groups. The results indicated that while soil microbial biomass may change across different soil environments after long‐term succession, soil microbial community structure can remain relatively stable. The results further indicated that soil microbes may show different successional patterns in different stages of succession. [ABSTRACT FROM AUTHOR]

Abstract: Establishment of an appropriate vegetation system for reclamation of saline‐sodic soils requires studies for specific salt‐affected region(s). The phytoremediation of saline‐sodic soils has not been well documented in the Songnen Plain of northeast China. Thus, in this study, we aimed to investigate the effects of grass (G) and maize (Zea mays L.; M) vegetation systems, which were established for 5 years, on soil properties of 10 typical saline‐sodic sampling sites across the Songnen Plain, in comparison with respective nonvegetated areas that were used as controls (CK) for the evaluation of variability among the sampling sites. Physicochemical properties, such as soil moisture, bulk density, porosity, saturated hydraulic conductivity, aggregate stability, pH, electric conductivity, total salt, organic C, total N, and C/N ratio, were analyzed. G and M vegetation significantly produced a 108% and 153% improvement in soil quality, respectively. Additionally, metagenomic analysis of the soil bacterial community revealed that vegetation enhanced the ability of the bacteria to survive in saline‐sodic soils, relative to the control. The composition of the bacterial community was highly correlated with all of the soil physicochemical properties. G vegetation had better effects than M vegetation in enhancing soil organic C, total N and aggregate stability, whereas M vegetation more favorably adjusted soil pH, physical structure, and bacterial community than G vegetation did. Collectively, these findings demonstrate that M vegetation has a greater impact than G vegetation on repairing saline‐sodic soils in the Songnen Plain of northeast China. [ABSTRACT FROM AUTHOR]

Sea buckthorn ( Hippophae rhamnoides L.) is a pioneer plant used for land reclamation and an appropriate material for studying the interactions of symbiotic microorganisms because of its nitrogen-fixing root nodules and mycorrhiza. We used high-throughput sequencing to reveal the diversities and community structures of rhizospheric fungi and their link with nitrogen-fixing Frankia harbored in sea buckthorn collected along an altitude gradient from the Qinghai Tibet Plateau to interior areas. We found that the fungal diversities and compositions varied between different sites. Ascomycota, Basidiomycota, and Zygomycota were the dominant phyla. The distribution of sea buckthorn rhizospheric fungi was driven by both environmental factors and the geographic distance. Among all examined soil characteristics, altitude, AP, and pH were found to have significant ( p < 0.05) effect on the rhizospheric fungal community. The rhizospheric fungal communities became more distinct as the distance increased. Moreover, co-inertia analysis identified significant co-structures between Frankia and AMF communities in the rhizosphere of sea buckthorn. We conclude that at the large scale, there are certain linkages between nitrogen-fixing bacteria and the AMF expressed in the distributional pattern. [ABSTRACT FROM AUTHOR]

Background: The Songnen Plain in northeast China was one of three major grasslands in China and has now become one of the most concentrated areas of sodic‐saline soil worldwide due to soil parent material characteristics, hydrological conditions, and overgrazing. Aims: The aim of this study was to evaluate the direct effects of environmental factors in shaping prokaryotic communities under three natural contiguous areas (severe saline‐alkaline field with no vegetation, moderate saline‐alkaline field with Suaeda glauca, and mildly saline‐alkaline field with natural grass vegetation) on the Songnen Plain in northeast China. Methods: Physicochemical properties of the soil pH, electric conductivity (EC), and soil organic carbon (SOC) were determined in three soil types with or without vegetation, while the metabarcoding analysis of the prokaryotic diversity and composition were analyzed by Illumina Miseq sequencing. Results: Our study revealed that the moderate and mildly saline‐alkaline soil exhibited lower pH by 0.614% and 10.17%, and significantly lower EC by 47.96% and 89.22%, respectively, in comparison to severe saline‐alkaline field soil. Prokaryotic 16S rRNA gene amplicon analysis revealed that mildly saline‐alkaline soil with native grasses had significantly higher alpha‐diversity. The composition of the prokaryotic community was highly correlated with the soil physicochemical properties, but the SOC was the most important driving forces for the prokaryotic composition. Random matrix theory (RMT) network analysis revealed the keystone operational taxonomic unit (OTU) (OTU3096, OTU137, OTU3198 and OTU2210) that was significantly affected by the soil physicochemical properties in the three contiguous areas. Conclusions: Collectively, these findings demonstrate that the mildly saline‐alkaline soil with natural grass vegetation has a beneficial impact on the soil physical properties and prokaryotic community relative to severe saline areas in the Songnen Plain of northeast China. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the preventive effects of Korean red ginseng (KRG) on gentamicin (GM)-induced ototoxicity and to identify the effective components of KRG., Study Design: In vivo and in vitro studies., Methods: Thirty-five Sprague-Dawley rats were divided into four groups. The GM group (n = 15) received intraperitoneal injections (IPI) of GM (160 mg/kg) for 5 days. The KRG + GM group (n = 12) was treated with intragastric feeding of KRG (500 mg/kg) for 12 days with 5 days of IPIs of GM. KRG (n = 4) and control (n = 4) groups were treated with KRG and saline, respectively. Auditory brainstem response (16 or 32 kHz) and Rotarod treadmill tests were done before and after treatments. Cochleas were evaluated by a scanning electron microscope (SEM) and phalloidin staining. Ginsenosides Rb1, Rb2, Rg1, and Re were evaluated as the water-soluble terazolium salt assay, annexin V/propidium iodide assay, and Western blots in HEI-OC1 cells., Results: Posttreatment hearing thresholds in GM, KRG + GM, KRG, and control groups were: 27.7 ± 7.2 dB, 23.1 ± 4.1 dB, 16.9 ± 2.6 dB, and 21.3 ± 3.5 dB, respectively, for 16 kHz, 30.5 ± 6.6 dB, 25.2 ± 4.3 dB, 22.5 ± 2.7 dB, and 22.5 ± 3.8 dB, respectively for 32 kHz. The KRG + GM group had significantly better hearing than the GM group (P < .05). On SEM and phalloidin staining, the GM group showed severe loss of stereocilia in the basal outer hair cells and a few losses in the middle turns, whereas the KRG + GM group showed relatively intact hair cells. Balance impairment in treadmill tests was not definite in any group. Rb1 and Rb2 showed more effective protection than other components., Conclusions: KRG protects against GM-induced hearing loss and hair cell death in rats. Laryngoscope, 2011., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)